As a liquid discharge apparatus according to the background art, a liquid jetting head disclosed is known. In an example of the liquid jetting head, a spacer is interposed between an actuator substrate and a sealing plate. The spacer is attached to the actuator substrate through an adhesive so as to surround a bump electrode protruding from the actuator substrate toward the sealing plate. Furthermore, piezoelectric element constituting the actuator substrate is disposed outside the closed space surrounded by the spacer.
In another example of the liquid jetting head, a frame-shaped spacer is provided between a sealing plate and an actuator substrate so as to surround a piezoelectric element. The piezoelectric element is displaced to cause a pressure variation of liquid in a pressure chamber formed in the actuator substrate, such that the liquid is jetted from a nozzle communicating with the pressure chamber.